Vacuum gun



T. J. SCALA June 19, 1962 VACUUM GUN 2 Sheets-Sheet 1 Filed Aug. 6, 1959FIG. 2

FIG. 5

THOMAS J. SCALA INVENTOR ATTORNEY T. J. SCALA June 19, 1962 VACUUM GUN 2Sheets-Sheet 2 Filed Aug. 6, 1959 THOMAS J. SCALA INVENTOR ATTORNEYUnited States Patent 3,039,450 VACUUM GUN Thomas I. Scala, LakeHopatcong, N .J., assignor to Astrosysterns, Incorporated, Livingston,NJ a corporation of New Jersey Filed Aug. 6, 1959, Ser. No. 831,993 7Claims. (Cl. 124-11) This invention relates to a vacuum gun for throwinga projectile through the air to a point some distance from the gunbarrel. It has particular reference to a gun which operates withoutexplosives, compressed air, or hydraulic pressure. The only means forconveying the missile is due to the pressure difierence between theatmospheric pressure and a vacuum Within the gun barrel.

The majority of guns in existence today propel a missile by means of thepressure derived from an exploding mass. All these guns have thedisadvantage of producing a recoil and considerable heat andincandescent gas. Some guns have been made which use compressed gas asthe propellant. These guns also produce a recoil and require a heavy gunbarrel which is able to withstand the pressure of the compressed gas.

The present invention operates entirely by means of atmospheric pressureand for this reason there is no recoil to the gun, there is no heatgenerated in the gun or in the missile and there is no flash or dangerof fire anywhere within the vicinity of the gun. The only recoil whichis possible with this type of gun is the slight frictional drag producedby the missile as it travels through the barrel and this force isexerted in the same direction the missile takes instead of the oppositedirection. In explosive type guns the force generated by the explosivechemical exerts a maximum force shortly after it has been exploded, thenthe pressure diminishes as the projectile travels through the barrel andis almost Zero as the missile leaves the barrel. In the vacuum type gunthe pressure is constant throughout the entire travel of the missilethrough the length of the barrel.

One of the objects of this invention is to provide an improved gun whichavoids one or more of the disadvantages and limitations of prior artguns.

Another object of the invention is to throw a heavy projectile adistance from the gun at a reduced cost as compared to other types ofguns now in use.

Another object of the invention is to increase the safety of guns byreducing the danger of explosion, the danger of fire, and the danger ofexploding the barrel.

Another object of the invention is to provide a gun having substantiallyno recoil.

Another object of the invention is to provide a gun which gives constantmaximum acceleration to a missile throughout the entire length of thegun barrel.

Another object of the invention is to provide a gun which is essentiallynoiseless and produces no visible flash.

Another object of the invention is to reduce the heat expended duringthe projection of the missile.

The invention comprises a vacuum gun for projecting a missile aconsiderable distance from the gun and includes a hollow cylindricalbarrel having a removable closure means at one end and an opening at theother end for inserting a missile. The missile is held by a releasablemeans at one end of the barrel and a vacuum pump is 3,039,450 PatentedJune 19, 1962 provided for removing the air from the barrel prior tofiring.

For a better understanding of the present invention, together with otherand further objects thereof, reference is made to the followingdescription taken in connection with the accompanying drawings.

FIG. 1 is a side view of the gun showing its mounting and a vacuum pumpconnected to the barrel.

FIG. 2 is a cross sectional view of the barrel shown in FIG. 1.

FIG. 3 is a cross sectional view of the barrel shown in FIG. 1 and istaken along line 3-3 of that figure.

FIG. 4 is a cross sectional view showing an alternate closure means forthe barrel.

FIG. 5 is an end view of the closure means shown in FIG. 4.

FIG. 6 is a cross sectional view of a portion of the closure means shownin FIGS. 4 and 5.

FIG. 7 is still another alternate means for closing one end of thebarrel.

FIG. 8 is a sectional view of a means of closing the end of the gin anda system which removes the end prior to the arrival of the missile.

FIG. 9 is an end view (with a portion in section) of the gun shown inFIG. 8.

FIG. 10 is a sectional view of an alternate means for releasing the endcover just before the missile arrives at the tube end.

FIG. 11 is a cross sectional view of the barrel shown in FIG. 10 and istaken along the line 1111 of that figure.

Referring now to FIGS. 1, 2, and 3, the gun comprises a hollowcylindrical tube 10 which is closed at one end with a cap 11 andincludes a missile 12 inserted in the other end. The gun is mounted bymeans of two stub shafts 13 and 14 which are journaled in uprightsupports 15 and 16 set on a base 17. The missile 12 is made with an eyeor hook 18 so that it may be releasably secured by means of a string 20secured to a bracket 21 which is fastened to a portion of the barrel.FIG. 1 shows a string 20 which retains the missile 12, this string beingdesigned to be clipped by a cutting tool when the missile is to bepropelled through the gun barrel. It is understood that other forms ofreleasable mechanisms may be used and a missile launched by a triggermechanism which releases the missile.

In order to operate the gun, a vacuum must be pumped to remove the airfrom the interior of the barrel. The easiest way to do this is by amechanical vacuum pump 22 connected to the barrel by a flexible conduit23 and run by means of a belt 24 coupled to an electric motor 25.However, the vacuum pump 22 may be turned by hand and other simplerforms of vacuum apparatus may be used. One of these is a liquidaspirator which removes air from an enclosure by means of a stream ofwater or other liquid passing through an orifice. It is obvious that thevacuum within the barrel does not have to be entirely free of air. Ithas been found by experiment that pressures of a few millimeters ofmercury produce substantially the same throwing power as pressures whichproximate one or two microns.

FIG. 2 shows the details of the closure means 11 which includes an 0ring 27 which seals one end against air leakage and the missile 12 whichcontains a charge 28 3 and two rings 30 and 31 for sealing the barrelwhile it is being pumped and during the passage of the missile throughthe barrel.

The cross sectional drawing of FIG. 3 indicates one way in which thebarrel It} may be mounted to facilitate rotation about a horizontalaxis. It will be obvious that many other forms of mounting can be usedand since there is no recoil, the barrel may be held in the arms withoutbenefit of any other mechanical support. It should be pointed out herethat the barrel may be made quite light, of thin aluminum material sinceit is only required to withstand the pressure of the atmosphere which isless than pounds per square inch.

The closure means shown in FIGS. 1 and 2 comprise a wooden or plasticcap which fits into one end of the barrel and which is blown out by theinertia of the missile when the gun is fired. Other forms of closuremeans may be used, an alternate form being shown in FIGS. 4, 5', land 6,where a four element conical cap 33 is placed over the end of thebarrel. The conical cap may be divided into four segments 34, 3'5, 36,and 37, and is retained on the barrel rim by an annular resilient ring38 of plastic or rubber. Leakage is prevented by means of an 0 ring 40and the four segments are coupled together by means of a rubber orplastic insert il shown in detail in FIG. 6. This conical closure isdesignated to open like a gate when the missile 12 is propelled throughth barrel. Other closure means may be provided for hinging the fourcomponents to the end of the barrel so that they will always beavailable after firing to close the end of the barrel in preparation fora second vacuum pumping and another firing.

The cross sectional view shown in FIG. 7 shows a second alternate meansfor closing the end of the barrel. This closure means includes a thickplastic sheet 43 placed over the open end of the barrel and retained inposition by a clamp 44 which may be a metallic clamp or a flexibleplastic ring which secures the periphery of the plastic disk to theoutside surface of the barrel. When this closure means is employed, themissile 12 may either puncture the diaphragm 43 or the entire structuremay be removed from the end of the barrel and carried with the missileto its destination.

The operation of the gun is obvious. The cap 11 is placed on one end andthe missile 12 is inserted into the other end with a releasable meansholding it in place. Then the inner space is exhausted by means of apump and when the pressure is reasonably low the string 26 is cut andthe missile is propelled along the barrel by atmospheric pressure. Withreasonably long barrels the velocity of the missile should increaseuniformly as it traverses the length of the barrel because theatmospheric pressure behind it is constant. On reaching the end of thebarrel the cap 11 is removed from the barrel due to the inertia of themissile and either falls to the ground or is carried along with themissile.

It will be obvious that the pressures exerted on the exterior of thebarrel never exceed atmospheric pressure, therefore the bar-rel may bemade of light material, even plastic. It is also evident that there isno flash, no danger of starting a fire, and no recoil. One of theapplications of this vacuum gun is the throwing of large barrels ofwater into a forest fire from considerable distances. In this type ofapplication the gain has the advantage of low weight, absence of firehazard, and considerable maneuverability in forest areas.

The gun shown in FIGS. 8 and 9 includes the usual barrel it anddetachable cover 11. In addition, a reentrant pipe 50 is joined to thebarrel at a point 51 intermediate between the barrel ends. The other endor" the pipe is also joined to the barrel at a point 52 close to thecover 11. A valve 53 is connected between the two ends to regulate theflow of air through the pipe.

This device operates as follows: When the missile is released, ittravels along the barrel propelled by atmospheric pressure. After itpasses point 51, air passes into the tube, through the valve 53, andinto the space between the missile and the cover 11. This air iscompressed by the missile and blows the cover off the end of the barrel,insuring that the missile shall have a free, unimpeded trajectory.

The gun cover shown in FIGS. 10 and 11 is still another device forremoving the end cover just before the missile arrives at the end of thebarrel. The barrel 10 is provided with a hinged cover 54, pivoted on apin 55, secured to a bracket 56 which is secured to the side of thebarrel 10. Cover 54 is engaged by three springs 57, 58, and 60 (see alsoFIG. 11) which press against the barrel side of the cover and are strongenough to open the cover even while it is held in its closed position byatmospheric pressure. While the barrel is being evacuated of air thecover 54 is held in place by a latch 61, pivoted at 62, and including apiston 63 which fits into a small chamber 64. The chamber 64 isconnected by a pipe 65 to an opening 66 which is intermediate the twoends of the barrel. Latch 61 is urged to an unlatch position by acompression spring 67 but this spring is chosen to permit the latch toremain in its latched position when the barrel is evacuated and thepiston 63 held in chamber 64 by atmospheric presure.

When the missile is released, it travels along the barrel, followed byatmospheric pressure and, when the missile passes opening 66,atmospheric pressure is admitted to pipe 65 and piston 63 is released.Spring 67 removes latch 61 from cover 54 and springs 57, 58, and 60force the cover open just before the arrival of the missile. in thismanner the missile is allowed to move into its natural trajectorywithout the hindrance of the cover or any of its components.

While there have been described and illustrated specific embodiments ofthe invention, it will be obvious that various changes and modificationscan be made in the barrel and in the vacuum pump without departing fromthe field of the invention which should be limited only by the scope ofthe appended claims.

I claim:

1. A vacuum gun for projecting a missile comprising, a hollowcylindrical barrel having a removable closure means at one end and anopening at the other end for inserting the missile, releasable means forrestraining the missile at one end of the barrel, and means for removingthe air from the barrel to create a partial vacuum therein prior toprojecting the missile.

2. A vacuum gun for projecting a missile comprising, a straight hollowcylindrical barrel having a removable closure means at one end and anopening at the other end for inserting the missile, releasable means forrestraining the missile at one end of the barrel, and a vacuum pump forremoving air from the barrel to create a partial vacuum therein prior toprojecting the missile.

3. A vacuum gun for projecting a missile comprising, a straight hollowcylindrical barrel having a removable air-tight closure means at one endand an opening at the other end for inserting the missile, releasablemeans for restraining the missile at said other end of the barrel, avacuum pump for removing air from the barrel to create a partial vacuumtherein prior to projecting the missile, and a flexible conduitconnected between the barrel and the vacuum pump.

4. A vacuum gun as set forth in claim 3 in combination with a missilewhich is formed with a plurality of encircling deformable rings forsealing the interior of the barrel against air leakage.

5. A vacuum gun as set forth in claim 3 wherein the closure means issealed against leakage by means of a deformable ring positioned in aslot in the closure body and making contact with the inside surface ofthe barrel.

6. A vacuum gun as set forth in claim 3 wherein said closure means isresiliently secured to the end of the barrel by a resilient band.

7. A vacuum gun for projecting a missile comprising,

References Cited in the file of this patent UNITED STATES PATENTSBostedo et a1. Sept. 4, Dinspel Mar. 31, Blurne July 18, Amdur Oct. 22,Halpern June 14, Kjellsen July 15,

